The R-Matrix with Pseudostates Method

T.W. GORCZYCA, N.R. BADNELL, D.C. GRIFFIN, D.M. MITNIK, AND M.S. PINDZOLA

Atomic Data Needs for X-ray Astronomy, edited by M.A. Bautista, T.R. Kallman and A.K. Pradhan

NASA Press

Lugar: Greenbelt, Maryland, USA; Año: 2000; p. 97 - 102

We review the development of pseudostate methods for treating electron-ion collision processes. We describe our implementation of these methods within the Wigner-Eisenbud R-matrix method. We present recent results for photoionization, electron-impact excitation, and electron-impact ionization, which demonstrate the importance of properly accounting for the two electron continuum. The comparison with experimental, as well as other theoretical, electron impact ionization results suggests that there may be inaccuracies in the overall normalization of earlier measurements. This is confirmed in the case of Al(2+) by a more recent experimental study. The implications regarding the use of excitation and ionization rates from existing databases for modeling astrophysical plasmas are discussed.